Three-dimensional structure of the 67K N-terminal fragment of E. coli DNA topoisomerase I.

Lima CD; Wang JC; Mondragon A

Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208.

Nature 367: 138-46 (1994)

Abstract
The three-dimensional structure of the 67K amino-terminal fragment of Escherichia coli DNA topoisomerase I has been determined to 2.2 A resolution. The polypeptide folds in an unusual way to give four distinct domains enclosing a hole large enough to accommodate a double-stranded DNA. The active-site tyrosyl residue, which is involved in the transient breakage of a DNA strand and the formation of a covalent enzyme-DNA intermediate, is present at the interface of two domains. The structure suggests a plausible mechanism by which E. coli DNA topoisomerase I and other members of the same DNA topoisomerase subfamily could catalyse the passage of one DNA strand through a transient break in another strand.

Mesh Headings

Amino Acid Sequence

Binding Sites

Crystallography, X-Ray

DNA Topoisomerase*

Escherichia coli*

Hydrogen Bonding

Models, Molecular

Molecular Sequence Data

Protein Conformation

Support, U.S. Gov't, P.H.S.

Database Cross References

genbank/x72391

Unique Identifier: 94159070

Chemical Identifiers (Names)

EC 5.99.1.2 (DNA Topoisomerase)